The wake of a slender body is generally thinner than its bluff body counterpart. Compared to the disk wake of CS20, the present unstratified wake is smaller by a factor of about 3 – contrast black lines in figure REF (a) to (b). The difference in wake size stems from the different near-wake features. Here, the initial non-dimensional wake width is around \(0.2\)  whereas its value for the disk is around 0.7. This observation agrees well with the scaling proposed by [1]} and used in stratified wake experiments by [2]}, where the wake dimensions behind a body with diameter \(D\)  scale with the drag coefficient \(\sqrt{C_D}\) . We find that \(C_D^{\mathrm {disk}} \approx 1.11\)  and \(C_D^{\mathrm {spheroid}} \approx 0.13\)  resulting in \((C_D^{\mathrm {disk}}/C_D^{\mathrm {spheroid}})^{0.5} \approx 3.2\) . Besides the initial dimensions, the near-wake growth rates of the spheroid and disk are also very different. Whereas in the \(x=3-20\)  region the spheroid unstratified wake grows as \(L \sim x^{0.2}\) , the disk wake grows as \(L \sim x^{0.45}\) . Later, the growth rate of both wakes becomes comparable but the difference in size is already established and dictated by the near wake.
